Methods for the controlled reduction of turbine nozzle flow areas and turbine nozzle components having reduced flow areas

Abstract

Embodiments of a method for controllably reducing of the flow area of a turbine nozzle component are provided, as are embodiments of turbine nozzle components having reduced flow areas. In one embodiment, the method includes the steps of obtaining a turbine nozzle component having a plurality of turbine nozzle flow paths therethrough, positioning braze preforms in the plurality of turbine nozzle flow paths and against a surface of the turbine nozzle component, and bonding the braze preforms to the turbine nozzle component to achieve a controlled reduction in the flow area of the turbine nozzle flow paths.

Description

TECHNICAL FIELD[0001]The following disclosure relates generally to gas turbine engines and, more particularly, to embodiments of a method for reducing the flow areas of turbine nozzle components, as well as to embodiments of turbine nozzle components having reduced flow areas.BACKGROUND[0002]During operation, a gas turbine engine compresses intake air, mixes the compressed air with fuel, and ignites the fuel-air mixture to produce combustive gasses, which are then expanded through a number of air turbines to drive rotation of the turbine rotors and produce power. Turbine nozzles are commonly positioned upstream of the turbine rotors to meter combustive gas flow, while also accelerating and turning the gas flow toward the rotor blades. A turbine nozzle typically assumes the form of a generally annular structure having a number of flow passages extending axially and tangentially therethrough. By common design, the turbine nozzle includes an inner endwall or shroud, which is generally ...

AI Technical Summary

Benefits of technology

The patent describes a new design for a turbine nozzle component that helps improve its performance. This design includes an inner and outer endwall with a large number of nozzle vanes in between. These vanes help to create flow paths through which gas can flow. These flow paths are important for the turbine's performance, and the patent proposes using braze preforms to reduce the area of these flow paths, which can make a big difference in the engine's efficiency. Overall, this design helps to improve the engine's performance by optimizing the flow of gas through the turbine nozzle.

Problems solved by technology

It is, however, difficult to manufacture a turbine nozzle having an ideal turbine flow area in an efficient, highly-controlled, and cost-effective manner.

For example, in instances wherein a number of individual turbine nozzle segments are separately cast and assembled to produce a turbine nozzle ring assembly, it is often difficult to produce nozzle segments having tightly controlled inner dimensions due to uncertainties inherent in the casting process, such as dimensional changes resulting from metal shrinkage during cooling.

While it is possible to fine tune part dimensions via the production of multiple molds in a trial-and-error process, such a practice is time consuming and may incur significant expense as each investment mold may cost several hundred thousand U.S. dollars to produce.

This solution is, however, less than ideal and may result in undesired distortion of the nozzle vanes, as well as obstruction of any cooling channels provided downstream of the metering points.

Furthermore, even if a turbine nozzle is initially produced to have an ideal or near-ideal effective flow area, gradual material loss due to hot gas erosion and / or abrasion of the nozzle vanes and endwalls during operation can result in the undesired enlargement of the turbine flow area over time, which may ultimately necessitate replacement of the turbine nozzle.

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